NTP Servers in France: Complete Guide & Comparison

NTP Pool France (fr.pool.ntp.org)

For the majority of use cases, the NTP pool France is the default choice. It is a geolocation-based DNS round-robin system that automatically redirects clients to nearby and reliable servers. Approximately 200 IPv4 servers participate in the France zone.

Advantages:

• Decentralized, community-driven, natively supported by all operating systems
• Reliable — the scoring system automatically removes failing servers
• RDEM Systems is an active contributing member of the pool with >10 Stratum 2 servers

Limitations:

• No NTS — the DNS round-robin mechanism is incompatible with NTS, because each server requires its own TLS certificate. You cannot authenticate a server whose address you do not know in advance.
• No choice of specific server (the pool decides)
• Variable quality depending on contributors

NTS in France — the current state

NTS (Network Time Security) authenticates and encrypts NTP exchanges, preventing interception and spoofing attacks. It is the future of the protocol, but its deployment remains marginal: approximately 60 to 70 public NTS servers worldwide, of which 45 to 50 are in Europe.

In France, the available NTS options can be counted on one hand:

Our NTS pool: ntp-pool.rdem-systems.com

European context: NTS reference operators

To put the French offering in perspective, here are the main NTS operators in Europe:

French Stratum 1 servers (primary sources)

French Stratum 2 servers

Independent and community-operated

Academic and research network (Renater)

Hyperscalers (anycast with nodes in France)

French NTP appliance manufacturers

These companies do not offer public NTP services, but they are part of the French time ecosystem. They design and manufacture NTP/PTP appliances for enterprise, defense, and industrial use.

• Bodet Time (Trementines, Maine-et-Loire) — since 1868. NETSILON range: GPS/GLONASS/Galileo/BeiDou, NTP/PTP, designed and manufactured in France. Multi-source (satellite, ALS162/DCF77 radio, network).
• Gorgy Timing (Buzancais, Indre) — since 1979. LEDI range. Clients in defense, aerospace, industry, and transportation.

Summary and positioning

French NTP infrastructure has historically relied on the academic world: universities, CNRS, grandes ecoles, research institutes. These servers are stable — some have been running for over 20 years — but aging: often NTP v3, hardware sometimes 20+ years old, no NTS support, unmaintained reference lists.

Key findings:

• The fr.pool.ntp.org pool (~200 IPv4 servers) remains the pragmatic default choice
• NTS is virtually absent in France: only 3 operators — RDEM Systems (>10 NTS servers), System76 (1 Parisian node), Viarouge (1 server in Nancy)
• Hyperscalers (Cloudflare, Google, Meta) offer massive but centralized, non-sovereign reliability
• French NTP hardware is well represented (Bodet, Gorgy) but it is an appliance market, not a public service

Recommended configuration

Standard usage: Chrony + FR pool

# /etc/chrony/chrony.conf
# NTP Pool France (primary source)
pool fr.pool.ntp.org iburst maxsources 4

# Complementary servers (French operator, Stratum 2)
server ntp1.rdem-systems.com iburst
server ntp2.rdem-systems.com iburst

# Fast sync on startup
makestep 1 3
rtcsyncCopy

Secure usage: Chrony + NTS

# /etc/chrony/chrony.conf - with NTS
# FR pool as base (NTS not possible on the pool)
pool fr.pool.ntp.org iburst maxsources 3

# French NTS servers (authentication + encryption)
server ntp1.rdem-systems.com iburst nts
server ntp2.rdem-systems.com iburst nts
server ntp3.rdem-systems.com iburst nts

makestep 1 3
rtcsyncCopy

High precision: Chrony + NTS + institutional Stratum 1

# /etc/chrony/chrony.conf - maximum precision
# Institutional Stratum 1 (notify operator before use)
server ntp-p1.obspm.fr iburst

# French NTS servers
server ntp1.rdem-systems.com iburst nts
server ntp2.rdem-systems.com iburst nts

# FR pool as complement
pool fr.pool.ntp.org iburst maxsources 2

makestep 1 3
rtcsyncCopy

Windows (w32tm)

REM French NTP servers (FR pool + RDEM Systems)
w32tm /config /manualpeerlist:"0.fr.pool.ntp.org 1.fr.pool.ntp.org ntp1.rdem-systems.com ntp2.rdem-systems.com" /syncfromflags:manual /reliable:yes /update
net stop w32time && net start w32time
w32tm /resyncCopy

Frequently asked questions

Does pool.ntp.org support IPv6?

Partially. Approximately 30% of servers in pool.ntp.org (and a similar share in fr.pool.ntp.org) publish an AAAA record in addition to A — the exact proportion varies with NTP Pool scoring and currently active servers. RDEM Systems exposes every NTP server as dual-stack IPv4/IPv6. For a NIS 2 / ISO 27001 compliant architecture, plan at least one IPv6 source in addition to your IPv4 sources. Test IPv6 connectivity of your NTP source →

Is there an NTS pool?

Yes. RDEM Systems operates ntp-pool.rdem-systems.com, one of the first public NTS pools available. It automatically distributes requests across more than 10 NTS servers in dual-stack IPv4/IPv6, with authentication and encryption enabled by default. A single line of configuration is enough: server ntp-pool.rdem-systems.com iburst nts. Learn more about NTS (Network Time Security) →

Is there a French NTS pool?

Yes — ntp-pool.rdem-systems.com is entirely operated in France on the AS206014 network (Equinix Paris hosting) with peering at French IXPs (FranceIX, Equinix IXP Paris). Unlike anycast US solutions (Cloudflare, AWS), every node is physically located in France — typical latency 1 to 3 ms from French ISPs. See the full list of NTS servers in France or the dedicated NTS page.

How do I check if a French NTP server is still active?

The fast command-line method: ntpdate -q server.example.fr displays offset and stratum without modifying the local clock. Modern alternative: chronyd -Q 'server server.example.fr iburst minpoll 2 maxpoll 2'. For an in-browser diagnostic without installing an NTP client, use check-ntp.net: it queries the source from our AS206014 network and returns latency, stratum, NTS response and IPv6 support.

Can I contribute to the French NTP pool?

Yes, any operator with a stable public IP can join ntppool.org. Prerequisites: fixed IP (no NAT), synchronization within 100 ms of a reliable source, accepting ~10 req/s on average. RDEM Systems has contributed to the FR pool since 2005 with over 10 servers. See why contribute to the NTP pool and our guide run an NTP pool server.

What is the typical latency to a French NTP server from Paris?

For a French source well peered at a Paris IXP, expect 1 to 3 ms RTT. A German server (PTB Braunschweig): 10–20 ms. A Swedish server (Netnod): 25–40 ms. A US server (NIST): 80–150 ms. Low latency reduces RTD and improves offset precision. Detailed measurements at the European NTP latency benchmark.

French Stratum 1 or Stratum 2: which should I choose?

A Stratum 1 server synchronizes directly to a primary reference (GNSS, atomic clock, PPS). A Stratum 2 synchronizes through one or more Stratum 1 servers. For 99% of use cases (application servers, workstations, monitoring), a well-chosen Stratum 2 offers more than sufficient precision (< 1 ms). A local Stratum 1 is only justified by strict regulatory requirements (MiFID II, eIDAS, defense) or air-gapped environments. Understand NTP stratum levels →